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| 1 # Copyright (c) 2011 The Chromium Authors. All rights reserved. | |
| 2 # Use of this source code is governed by a BSD-style license that can be | |
| 3 # found in the LICENSE file. | |
| 4 | |
| 5 import logging | |
| 6 import re | |
| 7 import telnetlib | |
| 8 | |
| 9 | |
| 10 class PowerStrip(object): | |
| 11 """Controls Server Technology CW-16V1-C20M switched CDUs. | |
| 12 (Cabinet Power Distribution Unit) | |
| 13 | |
| 14 This class is used to control the CW-16V1-C20M unit which | |
| 15 is a 16 port remote power strip. The strip supports AC devices | |
| 16 using 100-120V 50/60Hz input voltages. The commands in this | |
| 17 class are supported by switches that use Sentry Switched CDU Version 6.0g. | |
| 18 | |
| 19 Opens a new connection for every command. | |
| 20 """ | |
| 21 | |
| 22 TIMEOUT = 10 | |
| 23 | |
| 24 def __init__(self, host, user='admn', password='admn'): | |
| 25 self._host = host | |
| 26 self._user = user | |
| 27 self._password = password | |
| 28 | |
| 29 def PowerOff(self, outlet): | |
| 30 """Powers off the device that is plugged into the specified outlet. | |
| 31 | |
| 32 Args: | |
| 33 outlet: The outlet ID defined on the switch (eg. .a14). | |
| 34 """ | |
| 35 self._DoCommand('off', outlet) | |
| 36 | |
| 37 def PowerOn(self, outlet): | |
| 38 """Powers on the device that is plugged into the specified outlet. | |
| 39 | |
| 40 Args: | |
| 41 outlet: The outlet ID defined on the switch (eg. .a14). | |
| 42 """ | |
| 43 self._DoCommand('on', outlet) | |
| 44 | |
| 45 def _DoCommand(self, command, outlet): | |
| 46 """Performs power strip commands on the specified outlet. | |
| 47 | |
| 48 Sample telnet interaction: | |
| 49 Escape character is '^]'. | |
| 50 | |
| 51 Sentry Switched CDU Version 6.0g | |
| 52 | |
| 53 Username: admn | |
| 54 Password: < password hidden from view > | |
| 55 | |
| 56 Location: | |
| 57 | |
| 58 Switched CDU: on .a1 | |
| 59 | |
| 60 Outlet Outlet Outlet Control | |
| 61 ID Name Status State | |
| 62 | |
| 63 .A1 TowerA_Outlet1 On On | |
| 64 | |
| 65 Command successful | |
| 66 | |
| 67 Switched CDU: < cdu cmd > | |
| 68 | |
| 69 Args: | |
| 70 command: A valid CW-16V1-C20M command that follows the format | |
| 71 <command> <outlet>. | |
| 72 outlet: The outlet ID defined on the switch (eg. .a14). | |
| 73 """ | |
| 74 tn = telnetlib.Telnet() | |
| 75 # To avoid 'Connection Reset by Peer: 104' exceptions when rapid calls | |
| 76 # are made to the telnet server on the power strip, we retry executing | |
| 77 # a command. | |
| 78 retry = range(5) | |
| 79 for attempt in retry: | |
| 80 try: | |
| 81 tn.open(self._host, timeout=PowerStrip.TIMEOUT) | |
| 82 resp = tn.read_until('Username:', timeout=PowerStrip.TIMEOUT) | |
| 83 assert 'Username' in resp, 'Username not found in response. (%s)' % resp | |
| 84 tn.write(self._user + '\n') | |
| 85 | |
| 86 resp = tn.read_until('Password:', timeout=PowerStrip.TIMEOUT) | |
| 87 assert 'Password' in resp, 'Password not found in response. (%s)' % resp | |
| 88 tn.write(self._password + '\n') | |
| 89 | |
| 90 resp = tn.read_until('Switched CDU:', timeout=PowerStrip.TIMEOUT) | |
| 91 assert 'Switched CDU' in resp, 'Standard prompt not found in ' \ | |
| 92 'response. (%s)' % resp | |
| 93 tn.write('%s %s\n' % (command, outlet)) | |
| 94 | |
| 95 # Obtain the output of command and make sure it matches with the action | |
| 96 # we performed. | |
| 97 # Sample valid output: | |
| 98 # .A1 TowerA_Outlet1 On On | |
| 99 resp = tn.read_until('Switched CDU:', timeout=PowerStrip.TIMEOUT) | |
| 100 if not re.search('%s\s+\S+\s+%s\s+%s' % (outlet, command, command), | |
| 101 resp, re.I): | |
| 102 raise Exception('Command \'%s\' execution failed. (%s)' % | |
| 103 (command, resp)) | |
| 104 | |
| 105 # Exiting the telnet session cleanly significantly reduces the chance of | |
| 106 # connection error on initiating the following telnet session. | |
| 107 tn.write('exit\n') | |
| 108 tn.read_all() | |
| 109 | |
| 110 # If we've gotten this far, there is no need to retry. | |
| 111 break | |
| 112 except Exception as e: | |
| 113 logging.debug('Power strip retry on cmd "%s". Reason: %s' | |
| 114 % (command, str(e))) | |
| 115 if attempt == retry[-1]: | |
| 116 raise Exception('Sentry Command "%s" failed. ' | |
| 117 'Reason: %s' % (command, str(e))) | |
| 118 finally: | |
| 119 tn.close() | |
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